This invention relates to a vertical machining center with a tool slide, which can be moved in a controlled manner, and with a workpiece feed on one side of a machining area, where to change the workpieces between the workpiece feed and the machining area there is a moveable vertical machining center component that can be controlled in at least one axis.
A vertical machining center of the aforementioned class that is designed as a lathe is the subject matter of EP 0 539 837. In the prior art vertical machining center, a gripping device is mounted on the two opposite sides of the tool slide, which can be moved in two axes. By moving the tool slide, the gripping device can take from the workpiece feed individual workpieces, feed them to a chuck of a spindle and, after machining, convey them from the chuck to a tray.
In CNC controlled vertical machining centers, in particular 3 and 4 axis vertical—running stand—machining centers, one introduces for the purpose of automatically changing the workpieces the workpiece holders, which are often designed as workpiece clamping carriers and which have several workpieces clamped in the holders, into the working area of the vertical machining center by means of suitable manipulation and transport devices and then clamps the respective workpiece holder into a rotary table that has a horizontal axis of rotation and is either CNC-controlled or is controlled, for example, by positive stops. The workpiece holders can be designed both as pallets, for example, with two clamping sides respectively or as clamping turrets. In such a design several workpieces can be machined in succession by the respective multiple machining sides in one clamping operation without interruption; and thus one avoids the individual machining of workpieces and their space and time consuming clamping and unclamping operations.
This invention is based on the problem of designing a vertical machining center of the type described above in such a manner that several workpieces can be automatically changed simultaneously between the workpiece feed and/or a workpiece carrier magazine and the working area without having to make more complex the design of the vertical machining center.
This invention solves this problem in that the workpiece feed is designed for holding available and accepting workpiece holders with workpieces and is mounted so as to be in alignment with a CNC rotary table on that side of the vertical machining center, on which the respective workpiece holder is held by the CNC rotary table.
Due to this design of the vertical machining center, merely because of a linear movement several workpieces are fed simultaneously to the vertical machining center from a delivery position of a workpiece feed on a pallet or a clamping turret as far as into its working area. Therefore, altering a vertical machining center without automatic changing of the workpieces into a vertical machining center with automatic changing of the workpieces is relatively easy, especially since the existing CNC controlled components of the vertical machining center are used anyway for the linear movement.
The workpieces can be changed especially quickly and, therefore, the changing requires only that the vertical machining center be idle for a short period of time if the workpiece feed is designed as a magazine, the movement of which can be timed and which exhibits several receivers for workpiece holders. This embodiment makes it possible to change workpiece holders in the magazine during the machining operation of the vertical machining center, so that, when the vertical machining center is idle, a desired workpiece holder can be ready immediately for takeover.
The construction of the workpiece feed is especially simple, when it has a magazine wheel, which carries the receivers and can be swiveled about a central axis.
The vertical machining center can be simplified, when, according to another improvement of the invention, the CNC rotary table can be moved on guides in the direction of the workpiece feed for the purpose of changing the workpiece holders.
In vertical machining centers, which are designed as vertical milling machines, there is often, in addition to the rotary table, a counter-vise for holding the workpiece holder on the side, facing the workpiece feed and facing away from the CNC rotary table. In such a case the invention can provide that the counter-vise is mounted at right angles to the CNC rotary table so as to be traversable with the workpiece holder out of the collision area. Then the workpiece holders can be changed merely by moving the CNC rotary table.
However, it is also possible to change the workpiece holders with the counter-vise. This is especially easy in the vertical machining center if the counter-vise has a holder for clamping the workpiece carrier, which is designed for swiveling the respective workpiece carrier 180 deg. between a position facing the CNC rotary table and a position facing the workpiece feed, and if the counter-vise is traversable on guides in the direction of the workpiece feed.
Thus, there is no need for one part of the displacing drives, including the related measuring systems of the CNC rotary table or counter-vise, because to move the CNC rotary table or the counter-vise, the tool slide and the CNC rotary table or the counter-vise have docking means. Thus, there is the possibility that the tool slide drags the CNC rotary table or the counter-vise into the desired position.
An alternative to the aforementioned embodiments can also provide that to change the workpiece holders the tool slide has a gripper 24. This gripper docks on the side of the workpiece holder, in order to convey it then by means of its three CNC controlled linear movements from the working area directly into the workpiece carrier magazine and to deposit it there, in order to subsequently remove from its magazine the next new workpiece holder, to lift it in the same manner back into the working area and to deliver it there again to the rotary table clamping device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.